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<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        // 1.创建xhr对象
        let xhr = new XMLHttpRequest()
        // 2.调用open
        xhr.open('POST','http://www.liulongbin.top:3006/api/addbook')
        // 3.设置Content-Type属性,这是一个固定写法
        xhr.setRequestHeader('Content-Type','application/x-www-form-urlencoded')
        // 4.调用send() 将数据以查询字符串的形式发送给服务器
        xhr.send('bookname=水浒传&author=施耐庵')
        // 5.监听onreadystatechange事件
        xhr.onreadystatechange = ()=>{
            if(xhr.readyState === 4 && xhr.status === 200) console.log(xhr.responseText);
        }
    </script>
</body>
</html>